19-3054; Rev 1a; 2/04
3.5- and 4.5-Digit, Single-Chip ADCs with LED
Drivers and µC Interface
General Description
The MAX1497/MAX1499 low-power, 3.5- and 4.5-digit,
analog-to-digital converters (ADCs) with integrated light-
emitting diode (LED) drivers operate from a single 2.7V
to 5.25V power supply. They include an internal refer-
ence, a high-accuracy on-chip oscillator, and a multi-
plexed LED display driver. An internal charge pump
generates the negative supply needed to power the
integrated input buffers for single-supply operation. The
ADC is configurable for either a ±2V or ±200mV input
range and it outputs its conversion results to an LED
and/or to a microcontroller (µC). Microcontroller
communication is possible through an SPI™-/QSPI™-
/MICROWIRE™-compatible serial interface. The
MAX1497 is a 3.5-digit (±1999 count) device and the
MAX1499 is a 4.5-digit (±19,999 count) device.
The MAX1497/MAX1499 do not require external preci-
sion integrating capacitors, autozero capacitors, crystal
oscillators, charge pumps, or other circuitry required
with dual-slope ADCs (commonly used in panel meter
circuits).
These devices also feature on-chip buffers for the dif-
ferential signal and reference inputs, allowing direct
interface with high-impedance signal sources. In addi-
tion, they use continuous internal offset-calibration and
offer >100dB rejection of 50Hz and 60Hz line noise.
Other features include data hold and peak detection,
overrange and underrange detection, and a user-pro-
grammable low-battery monitor.
The MAX1499 is available in a 32-pin, 7mm
✕
7mm
TQFP package and the MAX1497 is available in 28-pin
SSOP and 28-pin PDIP packages. All devices in this
family operate over the -40°C to +85°C extended tem-
perature range.
Features
♦
High Resolution
MAX1499: 4.5 Digits (±19,999 Count)
MAX1497: 3.5 Digits (±1999 Count)
♦
Sigma-Delta ADC Architecture
No Integrating Capacitors Required
No Autozeroing Capacitors Required
>100dB of Simultaneous 50Hz and 60Hz
Rejection
♦
Operate from a Single 2.7V or 5.25V Supply
♦
Selectable Input Range of ±200mV or ±2V
♦
Selectable Voltage Reference: Internal 2.048V or
External
♦
Internal High-Accuracy Oscillator Needs No
External Components
♦
Automatic Offset Calibration
♦
Low Power (Exclude LED Driver Current)
Maximum 664µA Operating Current
Maximum 268µA Shutdown Current
♦
Small 32-Pin, 7mm x 7mm TQFP Package (4.5
Digits), 28-Pin SSOP Package (3.5 Digits)
♦
Also Available in a PDIP Package (3.5 Digits)
♦
Multiplexed LED Drivers
Resistor-Programmable Segment Current
♦
SPI-/QSPI-/MICROWIRE-Compatible Serial
Interface
♦
Extended Temperature Range (-40°C to +85°C)
MAX1497/MAX1499
Applications
Digital Panel Meters
Hand-Held Meters
Digital Voltmeters
Digital Multimeters
PART
MAX1497EAI*
MAX1497EPI
MAX1499ECJ
Ordering Information
TEMP RANGE
PIN-
RESOLUTION
PACKAGE
(DIGITS)
3.5
3.5
4.5
-40°C to +85°C 28 SSOP
-40°C to +85°C 28 PDIP
-40°C to +85°C 32 TQFP
*Future
product—contact factory for availability.
Pin Configurations appear at end of data sheet.
SPI/QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
3.5- and 4.5-Digit, Single-Chip ADCs with LED
Drivers and µC Interface
MAX1497/MAX1499
ABSOLUTE MAXIMUM RATINGS
AV
DD
to GND (MAX1499).........................................-0.3V to +6V
DV
DD
to GND (MAX1499) ........................................-0.3V to +6V
AIN+, AIN- to GND (MAX1499) ...........VNEG to (AV
DD
to +0.3V)
REF+, REF- to GND (MAX1499) ......... VNEG to (AV
DD
to +0.3V)
LOWBATT to GND (MAX1499) ................-0.3V to (AV
DD
+ 0.3V)
CLK,
EOC, CS,
DIN, SCLK,
DOUT to GND (MAX1499) .......................-0.3V to (DV
DD
+ 0.3V)
VNEG to GND (MAX1499) .......................-2.6V to (AV
DD
+ 0.3V)
LED_EN to GND (MAX1499)....................-0.3V to (DV
DD
+ 0.3V)
ISET to GND (MAX1499)..........................-0.3V to (AV
DD
+ 0.3V)
V
DD
to GND (MAX1497) ...........................................-0.3V to +6V
AIN+, AIN- to GND (MAX1497)..............VNEG to (V
DD
to +0.3V)
REF+, REF- to GND (MAX1497) ........... VNEG to (V
DD
to +0.3V)
CLK,
EOC, CS,
DIN, SCLK,
DOUT to GND (MAX1497)..........................-0.3V to (V
DD
+ 0.3V)
VNEG to GND (MAX1497)..........................-2.6V to (V
DD
+ 0.3V)
ISET to GND (MAX1497) ............................-0.3V to (V
DD
+ 0.3V)
VLED to GLED ..........................................................-0.3V to +6V
GLED to GND ........................................................-0.3V to +0.3V
SEG_ to GLED..........................................-0.3V to (VLED + 0.3V)
DIG_ to GLED ..........................................-0.3V to (VLED + 0.3V)
DIG_ Sink Current .............................................................300mA
DIG_ Source Current...........................................................50mA
SEG_ Sink Current ..............................................................50mA
SEG_ Source Current..........................................................50mA
Maximum Current Input into Any Other Pin ........................50mA
Continuous Power Dissipation (T
A
= +70°C)
32-Pin TQFP (derate 20.7mW/°C above +70°C).....1652.9mW
28-Pin SSOP (derate 9.5mW/°C above +70°C) ...........762mW
28-Pin PDIP (derate 14.3mW/°C above +70°C)......1142.9mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, GLED = 0, V
LED
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external reference)
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
DC ACCURACY
Noise-Free Resolution
Integral Nonlinearity (Note 1)
Range Change Ratio
Rollover Error
Output Noise
Offset Error (Zero Input Reading)
Gain Error
Offset Drift (Zero Reading Drift)
Gain Drift
INPUT CONVERSION RATE
External-Clock Frequency
External-Clock Duty Cycle
Conversion Rate
Internal clock
External clock, f
CLK
= 4.9152MHz
40
5
5
4.9152
60
MHz
%
Hz
Offset
V
IN
= 0 (Note 2)
(Note 3)
V
IN
= 0 (Note 4)
-0
-0.5
0.1
±1
INL
MAX1499
MAX1497
2.000V range
200mV range
(V
AIN+
- V
AIN-
= 0.100V) on 200mV range
(V
AIN+
- V
AIN-
= 0.100V) on 2.0V range
V
AIN+
- V
AIN-
= full scale
V
AIN-
- V
AIN+
= full scale
-19,999
-1999
±1
±1
10:1
±1
10
0
+0.5
+19,999
+1999
Count
Count
Ratio
Count
µV
P-P
Reading
%FSR
µV/°C
ppm/°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
3.5- and 4.5-Digit, Single-Chip ADCs with LED
Drivers and µC Interface
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, GLED = 0, V
LED
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external reference)
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
RANGE bit = 0
RANGE bit = 1
CONDITIONS
MIN
-2.0
-0.2
-2.2
Internal clock mode, 50Hz and 60Hz ±2%
Normal-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode Rejection
Input Leakage Current
Input Capacitance
Average Dynamic Input Current
LOWBATT TripThreshold
LOWBATT Leakage Current
Hysteresis
INTERNAL REFERENCE (REF- = GND, INTREF bit = 1) (bypass REF+ to GND with a 4.7µF capacitor)
REF Output Voltage
REF Output Short-Circuit Current
REF Output Temperature
Coefficient
Load Regulation
Line Regulation
Noise Voltage
0.1Hz to 10Hz
10Hz to 10kHz
Differential (V
REF+
- V
REF-
)
-2.2
Internal clock mode, 50Hz and 60Hz ±2%
Normal-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode 50Hz and 60Hz
Rejection (Simultaneously)
Common-Mode Rejection
Input Leakage Current
CMR
CMR
External clock mode, 50Hz and 60Hz ±2%,
f
CLK
= 4.9152MHz
For 50Hz and 60Hz ±2%, R
SOURCE
< 10kΩ
At DC
100
120
150
100
10
dB
TC
VREF
AV
DD
= V
DD
= 5V
I
SOURCE
= 0 to 300µA, I
SINK
= 0 to 30µA
V
REF
AV
DD
= V
DD
= 5V
2.007
2.048
1
40
6
50
25
400
2.048
+2.2
V
2.089
V
mA
ppm/°C
mV/µA
µV/V
µV
P-P
(Note 6)
-20
2.048
10
20
LOW-BATTERY VOLTAGE MONITOR (LOWBATT) (MAX1499 only)
V
pA
mV
CMR
CMR
External clock mode, 50Hz and 60Hz ±2%,
f
CLK
= 4.9152MHz
For 50Hz and 60Hz ±2%, R
SOURCE
< 10kΩ
At DC
100
120
150
100
10
10
+20
dB
TYP
MAX
+2.0
+0.2
+2.2
V
UNITS
ANALOG INPUTS (AIN+, AIN-) (bypass to GND with 0.1µF or greater capacitors)
AIN Input Voltage Range (Note 5)
AIN Absolute Input Voltage
Range to GND
MAX1497/MAX1499
dB
dB
nA
pF
nA
EXTERNAL REFERENCE (INTREF bit = 0) (bypass REF+ and REF- to GND with 0.1µF or greater capacitors)
REF Input Voltage
Absolute REF+, REF- Input
Voltage to GND
dB
dB
nA
_______________________________________________________________________________________
3
3.5- and 4.5-Digit, Single-Chip ADCs with LED
Drivers and µC Interface
MAX1497/MAX1499
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, GLED = 0, V
LED
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external reference)
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
Input Capacitance
Average Dynamic Input Current
CHARGE PUMP
Output Voltage
Input Current
VNEG
I
IN
C
VNEG
= 0.1µF
V
IN
= 0 or DV
DD
= V
DD
MAX1499
Input Low Voltage
V
INL
MAX1497
MAX1499
Input High Voltage
V
INH
MAX1497
Input Hysteresis
DIGITAL OUTPUTS (DOUT,
EOC)
Output Low Voltage
V
OL
I
SINK
= 1mA
I
SOURCE
= 200µA, MAX1499
Output High Voltage
V
OH
I
SOURCE
= 200µA, MAX1497
Tri-State Leakage Current
Tri-State Output Capacitance
POWER SUPPLY
(Note 10)
V
DD
Voltage
AV
DD
Voltage
DV
DD
Voltage
Power-Supply Rejection V
DD
Power-Supply Rejection AV
DD
Power-Supply Rejection DV
DD
V
DD
Current (Notes 8, 9)
V
DD
AV
DD
DV
DD
PSRR
PSRR
A
PSRR
D
I
VDD
MAX1497
MAX1499
MAX1499
(Note 7)
(Note 7)
(Note 7)
V
DD
= 5.25V
V
DD
= 3.3V
Standby mode
AV
DD
= 5.25V
AV
DD
Current (Notes 8, 9)
I
AVDD
AV
DD
= 3.3V
Standby mode
2.70
2.70
2.70
80
80
100
664
618
268
744
663
325
640
600
305
µA
µA
5.25
5.25
5.25
V
V
V
dB
dB
dB
I
L
C
OUT
DOUT only
DOUT only
0.8 x
DV
DD
0.8 x
V
DD
-1
15
+1
µA
pF
0.4
V
V
HYS
DV
DD
= V
DD
= 3.0V
0.7 x
DV
DD
0.7 x
V
DD
200
mV
-2.60
-10
-2.42
-2.30
+10
0.3 x
DV
DD
0.3 x
V
DD
V
µA
DIGITAL INPUTS (SCLK, DIN,
CS,
CLK)
(Note 6)
-20
SYMBOL
CONDITIONS
MIN
TYP
10
+20
MAX
UNITS
pF
nA
V
V
V
4
_______________________________________________________________________________________
3.5- and 4.5-Digit, Single-Chip ADCs with LED
Drivers and µC Interface
ELECTRICAL CHARACTERISTICS (continued)
(AV
DD
= DV
DD
= V
DD
= +2.7V to +5.25V, GND = 0, GLED = 0, V
LED
= +2.7V to +5.25V, V
REF+
- V
REF-
= 2.048V (external reference)
C
REF+
= C
REF-
= 0.1µF, C
VNEG
= 0.1µF. Internal clock mode, unless otherwise noted. All specifications are at T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
DV
DD
Current (Notes 8, 9)
LED Drivers Bias Current
LED DRIVERS
(Table 6)
LED Supply Voltage
LED Shutdown Supply Current
LED Supply Current
Display Scan Rate
Segment Current Slew Rate
DIG_ Voltage Low
Segment Drive Source Current
Matching
Segment Drive Source Current
Interdigit Blanking Time
V
LED
I
SHDN
I
LED
f
OSC
∆I
SEG
/∆t
V
DIG
∆I
SEG
I
SEG
V
LED
- V
SEG
= 0.6V, R
ISET
= 25kΩ
16
I
DIG_
= 176mA
LED driver shutdown mode
Seven segments and decimal point on,
R
ISET
= 25kΩ
MAX1499
MAX1497
176
512
640
25
0.178
±3
20
4
0.300
±10
25.5
2.70
5.25
10
V
µA
mA
Hz
mA/µs
V
%
mA
µs
SYMBOL
DV
DD
= 5V
I
DVDD
DV
DD
= 3.3V
Standby mode
From AV
DD
or V
DD
120
CONDITIONS
MIN
TYP
MAX
320
180
20
µA
µA
UNITS
MAX1497/MAX1499
_______________________________________________________________________________________
5
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